Cerebral palsy (CP) is a clinical diagnostic term referring to a group of upper motor neuron syndromes secondary to disorders of early brain development (Johnston, 1998a). In addition to primary impairments in motor function, there may be associated problems with speech, cognition, epilepsy, visual impairment seizures and orthopedic deformities. Although CP is considered non-progressive, neurological findings may change or progress over time (Saint Hilaire et al., 1991; Scott & Jankovic, 1996).

CP is the most prevalent and costly form of chronic motor disability that begins in childhood. Although comprehensive longitudinal studies are limited, the majority of affected children live into adulthood (Crichton et al., 1995). In the United States, financial costs of care are estimated to be in the billions of dollars (Kuban & Leviton, 1994). The non-economic impact on affected individuals and their families is substantial (Murphy et al., 2000).

At the end of the nineteenth century,William Osler published his lectures on The Cerebral Palsies of Children, with a CP classification based on neuroanatomy, etiology and extremity involvement. ‘Dividing the motor path into an upper corticospinal segment, extending from the cells of the cortex to the grey matter of the cord, and a lower spinomuscular, extending from the ganglia of the anterior horns to the motorial end plates, the palsies which I propose to consider have their anatomical seat in the former, and may result from a destructive lesion of the motor centres, or of the pyramidal tract, in hemisphere, internal capsule, crus or pons’ (Osler, 1987). The current concept of CP is built on Osler's description, using imaging techniques, molecular genetic probes and measurement tools to further etiological understanding, improve classification and refine treatment options (Hoon & Melhem, 2000; Brunstrom et al., 2000).

Several strongly conflicting theories of causation have been proposed. In the mid-1800s, Sir William Little suggested that most CP was related to difficulties with delivery, a view which has had legal ramifications extending to the present time (Little, 1861). Approximately 50 years later, Sigmund Freud offered an alternative hypothesis that cerebral palsy reflected ‘symptoms of deeper underlying influences which have dominated the development of the fetus’ (Freud, 1968). Recent epidemiological studies indicate that most cases are related to prenatal disorders of genetic and environmental origin (Hagberg et al., 1996; Palmer et al., 1995).